The facility layout problem is the arrangement of departments within a facility with
respect to some objectives such as material handling cost and distance travelled. In an
environment, where flows are fixed during the planning horizon, a static layout analysis
would be sufficient. The solution procedure can be formulated as a quadratic assignment
problem. In today’s market-based and dynamic environment, such flows can change
quickly due to changes in the design of an existing product, the addition or deletion of
a product, replacement of existing production equipment, shorter product life cycles and
changes in the production quantities and associated production schedule. The flows or
movements between pairs of departments in the layout are same but the distances may
change. If this changes warrant it, layout rearrangements may be planned in one or
more periods. The analysis is based on the tradeoff between the stable flow of
inefficient layouts and added distance between the departments. However, layout
analysis may not be justified in every situation. A Facility Layout Problem (FLP) is about
arranging the physical departments or machines within a facility to help the facility work in a productive way. A poor layout can lead to accumulation of work-in process
inventory, overloading of material handling system, inefficient setups and longer
queues. Therefore, solution of an FLP is a strategic study to be conducted. Traditionally,
there are two approaches for the FLP. The first one is the quantitative approach aiming
at minimizing the total distance travelled between departments or machines based on
a distance function. Due to the high complexity of computational of the FLP; there are
many efficient methods which can find good solutions in an acceptable time. Rosenblatt
(1986) was the first to present solution techniques for the Dynamic FLP (DFLP). He
developed an optimal solution methodology, identified bounding procedures, and
established heuristic techniques. Urban (1993) developed a steepest descent pair-wise
exchange technique similar to CRAFT. Conway and Venkataramanan (1994) used a
genetic algorithm to solve the DFLP, and Kaku and Mazzola (1997) used a tabu search
heuristic. Balakrishnan et al. (2000) improved the pair-wise exchange heuristic by
presenting a backward-pass pair-wise exchange heuristic with forecast windows.
Baykasoglu and Gindy (2001) presented a Simulated Annealing (SA) heuristic, and
Balakrishnan et al. (2003) presented a hybrid genetic algorithm for the DFLP. Dunker
et al. (Thomas et al., 2005) combined evolutionary computation and dynamic
programming for solving the DFLP.
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